Manufacturing method of a micro reconfigurable structure and its connection unit

Abstract

The present invention discloses a manufacturing method of a micro reconfigurable cell structure and its connection unit. The micro reconfigurable cell structure includes a parallel mechanism, and the parallel mechanism includes a platform and kinematic chains composed of a plurality of interconnected connection units. The connection unit includes a deformation part and at least two connection parts. The first end of the deformation part is connected to the first connection part among the connection parts, and the second end of the deformation part is connected to the second connection part among the connection parts. By changing the overall temperature of the micro reconfigurable cell structure, part or all of the deformation parts are caused to generate autonomous deformation to the corresponding memory shapes, the two connection parts connected to the first end and the second end of the deformation part change their relative spatial positions, and a conversion occurs between the platform and the kinematic chains, thereby realizing the switching of multiple reconfigurable cell forms, omitting the separate control devices and cables required in the prior art, and greatly reducing the control difficulty.

Description

Technical Field

[0001] The present invention relates to the field of micro-mechanical structures, and particularly to a manufacturing method of a micro reconfigurable cell structure and its connection unit. Background Art

[0002] A micro-mechanical structure refers to a mechanical structure with a characteristic length ranging from sub-millimeters to dozens of millimeters, and has the characteristics of small volume and light weight. Reconfigurable cell means that the topological structure of a mechanism is changed by a specific method, so that the number of components of the moving chain of the mechanism, the number of kinematic pairs, or the degrees of freedom are changed or converted. A micro reconfigurable cell structure refers to a micro-mechanical structure that realizes structural deformation through reconfigurable cells.

[0003] The reconfigurable cell mechanical structures in the prior art are usually large-scale structures (above centimeter level). For example, the volumes of the reconfigurable cell mechanical structures in the prior art (Tan N, Mohan R E, Elangovan K. Scorpio: A biomimetic reconfigurable rolling crawling robot [J]. International Journal of Advanced Robotic Systems, 2016, 13(5): 1-16. and Tian, Yaobin, Zhang, et al. A reconfigurable multi-mode mobile parallel robot [J]. Mechanism and Machine Theory, 2017, 111: 39-65.) are all at the centimeter level. The performance of the micro-mechanical structures manufactured based on large-scale structure manufacturing technologies (including the use of driving components, bearings, hinges, etc.) will be limited, so it is difficult to miniaturize. With the miniaturization of the structure scale, the dominant role of the surface effect will be greater than the Newtonian force, and along with the decline of the performance such as the stiffness and rotational speed of driving components and hinges, the performance requirements of micro-mechanical structures cannot be met (Wood R J, Avadhanula S, Sahai R, et al. Microrobot Design Using Fiber Reinforced Composites [J]. Journal of Mechanical Design, 2008, 130(5).).

[0004] In addition, existing metamorphic mechanical structures generally need to be connected to external devices through cables to obtain energy and control signals, and this state is called the tethered state. The metamorphic mechanical structure in the tethered state always needs to be dragged by cables (Baisch A T, Ozcan O, Goldberg B, et al. High speed locomotion for aquadrupedalmicrorobot[J]. International Journal of Robotics Research, 2014, 33(8):1063-1082.). For tasks such as minimally invasive surgery, repairing or assembling small and medium-sized structures or machines in industry, it is necessary to design a tetherless micro-mechanical structure that does not require cable connection. So far, the latest and most influential research progress on tetherless micro-mechanical structures is a micro-mechanical structure published in a sub-journal of Science in 2022 (Han M, Guo X, Chen X, et al. Submillimeter-scale multimaterial terrestrialrobots[J]. Science Robotics, 2022(66):7.). The impact factor of this article is as high as 27.54. This article uses shape memory alloy as the material of the rotating shaft of the series structure to achieve tetherless movement, without the need for complex electric power or liquid / gas pressure for driving. As is well known, shape memory alloy will deform when the temperature changes. In this article, in order to control the deformation of a specific rotating shaft of the micro-mechanical structure and prevent the deformation of the remaining specific rotating shafts, the method of global heating (that is, heating all components of the micro-mechanical structure together) cannot be adopted. Instead, it must be achieved by local heating of specific rotating shafts (that is, heating specific partial components of the micro-mechanical structure) (refer to Fig. 2 in this article and the last sentence on page 4). Global heating will cause all rotating shafts to deform (refer to Fig. 3 in this article and the corresponding illustration: left frames illustrate 3D robots under global heating: images with filled colors and black lines correspond to 3D geometries at room and elevated temperatures, respectively. Refer to the upper half of the leftmost first figure in Figures A-E of Fig. 3 in this article. When globally heated, all rotating shafts of the micro-mechanical structure deform).Due to the high requirements for heating accuracy in local heating, it is necessary to rely on external control devices (such as laser scanning devices) to achieve precise heating (refer to the abstract in this article). In summary, the technical inspiration given in this article is: in a micro-mechanical structure that combines a material that deforms with temperature as a rotating shaft, if the micro-mechanical structure is heated as a whole, it will inevitably cause all rotating shafts to deform. If precise control is required to make a specific rotating shaft deform while keeping the other specific rotating shafts from deforming, it can only be achieved through precise local heating. At the same time, as shown in Fig. 3 in this article for various obvious deformation situations, if obvious deformation of the micro-mechanical structure is to be achieved, it generally takes a relatively long time of dozens of seconds to hundreds of seconds.

[0005] Currently, no tetherless micro-mechanical structure has been found that can achieve overall collaborative controllability and rapid switching between different metamorphic forms solely through overall heating. The so-called overall collaborative controllability means that by overall heating, controlling a specific rotating shaft to produce a specific deformation while controlling the other specific rotating shafts not to deform. Summary of the Invention

[0006] To solve the deficiencies of the prior art, the present invention proposes a micro-metamorphic structure that achieves overall collaborative controllability solely through overall heating (global heating), precisely controls a specific rotating shaft to produce a specific deformation, and controls the other specific rotating shafts not to deform, thereby realizing a controllable metamorphic process of the micro-metamorphic structure and rapid switching between different metamorphic forms.

[0007] In a micro-mechanical structure incorporating a material that deforms with temperature, heating can precisely control the deformation of a specific rotating shaft while ensuring that the remaining specific rotating shafts do not deform. The prior art (Han M, Guo X, Chen X, et al. Submillimeter-scale multimaterial terrestrial robots[J]. Science Robotics, 2022(66):7.) provides the opposite teaching: local heating can only control the deformation of a specific rotating shaft and cannot prevent the remaining specific rotating shafts from deforming. Once heated, the material that deforms with temperature will inevitably deform. This application unexpectedly overcomes the technical prejudice of the prior art. By overall heating, it is possible to control the deformation of a specific rotating shaft while preventing the remaining specific rotating shafts from deforming, eliminating the need for a separate external control device (such as the laser scanning device in this article) required for local heating in the prior art. Through the overall synergistic effect of the material that deforms with temperature and the parallel mechanism, the present invention achieves rapid overall synergistic controllability simply through overall heating, precisely controlling the deformation of a specific rotating shaft while preventing the remaining specific rotating shafts from deforming, and completing a large deformation of the micro variable cell structure in a short time. The micro variable cell structure provided by the present invention can be used for tasks such as repairing or assembling small and medium-sized industrial structures or machines.

[0008] The technical solution adopted by the present invention is as follows: a micro variable cell structure, comprising a parallel mechanism, the parallel mechanism including a platform and kinematic chains composed of a plurality of interconnected connection units, the platform including a moving platform and a fixed platform, the connection unit including a deformation part and at least two connection parts, a first end of the deformation part being connected to a first connection part among the connection parts, a second end of the deformation part being connected to a second connection part among the connection parts. By changing the overall temperature of the micro variable cell structure, some or all of the deformation parts are caused to autonomously deform to corresponding memory shapes, and the spatial relative positions of the two connection parts connected to the first end and the second end of the deformation part are changed, resulting in a conversion between the platform and the kinematic chains, that is, the platform is converted into kinematic chains, and the kinematic chains are converted into a moving platform and a fixed platform, thereby realizing the switching of multiple variable cell forms of the micro variable cell structure.

[0009] The present invention utilizes the autonomous deformation of the deformation part and the overall cooperative effect of the parallel mechanism. Taking the deformation part as the rotating shaft, the micro variable cell structure can achieve overall cooperative control only relying on the change of the overall temperature, that is, controlling a specific rotating shaft to generate a specific deformation and controlling the remaining specific rotating shafts not to generate deformation, realizing the variable cell process corresponding to a specific screw, generating a controllable variable cell form, and realizing the controllable switching between different variable cell forms. Relying solely on the autonomous deformation of the deformation part or solely on the parallel mechanism cannot achieve the controllable variable cell process of the micro mechanical structure. It is necessary to organically combine the two to achieve overall cooperative control only by changing the overall temperature, enabling the micro mechanical structure to generate a specific variable cell process and achieve a specific variable cell form. The structure deformation involved in the present invention is completely different from the above-mentioned prior art (Han M, Guo X, Chen X, et al. Submillimeter-scale multimaterial terrestrial robots [J]. Science Robotics, 2022(66):7.), mainly including the following differences: In order to control a specific rotating shaft in the micro mechanical mechanism to generate deformation and control the remaining specific rotating shafts not to generate deformation, local heating must be used in this paper. However, the accuracy requirement for heating to achieve local heating is relatively high. Therefore, this paper needs to rely on a separate control device. The present invention can achieve overall cooperative control only relying on overall heating, that is, controlling a specific rotating shaft to generate deformation and controlling the remaining specific rotating shaft parts not to generate deformation by means of overall heating, and omitting the separate control device required for local heating in this paper.

[0010] The topological structure of the micro mechanical structure in this prior art does not change before and after deformation, and the size of the overall structure hardly changes before and after deformation (refer to Fig. 3 in this paper). The micro mechanical structure in the present invention realizes the transformation between the platform and the moving branch chain, that is, the platform is transformed into the moving branch chain, and the moving branch chain is transformed into the platform, resulting in a change in the topological structure. The micro mechanical structure generates variable cells, and then realizes the switching between different variable cell forms (refer to Figures 4A - 4C ) in the present invention. During the switching process between different variable cell forms, the scale change of the overall structure is as high as 26%, and the single scale change is as high as 125%.

[0011] The micro mechanical structure in this prior art takes dozens of seconds to hundreds of seconds to achieve obvious deformation (refer to various obvious deformation situations in Fig. 3 of this paper), and the change range of the deformation of the rotating shaft is about 0 - 30 degrees (refer to Fig. 1.C in this paper). The present invention can control the speed of obvious deformation within one second and can realize the switching between completely different variable cell forms (refer to Figures 4A - 4C ) in the present invention. The change range of the deformation of the rotating shaft controlled by the present invention can reach more than 100 degrees, and can control the remaining specific rotating shafts not to generate deformation.

[0012] The change in the overall temperature refers to the global heating of the micro metamorphic structure. The parallel mechanism includes a moving platform, a fixed platform, and at least two kinematic chains connecting the moving platform and the fixed platform. The autonomous deformation refers to the deformation generated only by the temperature change, which does not rely on external force loads, that is, this deformation is generated by the material itself. The corresponding memory shape means that the deformation part undergoes a specific deformation at a specific temperature, and this specific deformation is the memory shape. This memory shape can be achieved through heat treatment. The change in the relative spatial position means that the relative position between two connecting parts after the autonomous deformation of the deformation part is different from the relative position before the autonomous deformation of the deformation part. Preferably, this change refers to the change in the angle of the deformation part. The angle of the deformation part refers to the included angle between the extension directions of the two connecting parts connected to the deformation part. The first end and the second end of the deformation part are the connecting ends used to connect other components of the micro metamorphic structure when the connecting unit is part of the micro metamorphic structure, and the shape and relative position relationship of the first end and the second end are not limited. The deformation part may also include other ends, and the connecting parts do not only include two. As long as the connecting ends of the deformation part and the connecting parts can correspond one by one. For example, it can be 3 ends corresponding to 3 connecting parts, or 4 ends corresponding to 4 connecting parts, and so on.

[0013] Preferably, the different metamorphic forms refer to the initial form, the first metamorphic form, and the second metamorphic form.

[0014] Preferably, the micro metamorphic structure has an initial form. When the overall temperature of the micro metamorphic structure reaches the first temperature, the deformation parts on the kinematic chains generate autonomous deformation, causing the moving platform to rotate around the fixed platform, and the micro metamorphic structure realizes the switching between the initial form and the first metamorphic form.

[0015] Preferably, when the micro metamorphic structure realizes the switching between the initial form and the first metamorphic form, the change range of the angle of the deformation part on the kinematic chain is more than 100 degrees.

[0016] Preferably, the switching time between the initial form and the first metamorphic form of the micro metamorphic structure is within 2 seconds.

[0017] Preferably, based on the first metamorphic form, when the overall temperature of the micro metamorphic structure reaches the second temperature, and the second temperature is higher than the first temperature, a conversion occurs between the platform and the kinematic chains. After the conversion, the deformation parts on the obtained kinematic chains generate autonomous deformation, causing the obtained moving platform to perform a linear motion relative to the obtained fixed platform, and the micro metamorphic structure realizes the switching between the first metamorphic form and the second metamorphic form.

[0018] Preferably, when the micro metamorphic structure realizes the switching between the first metamorphic form and the second metamorphic form, the angular change amplitude of some deformation parts on the converted moving link is more than 100 degrees.

[0019] Preferably, the switching time for the micro metamorphic structure to realize the switching between the first metamorphic form and the second metamorphic form is within 0.4 seconds.

[0020] Preferably, the total switching time for the micro metamorphic structure to realize the transformation from the initial form to the first metamorphic form and then to the second metamorphic form is within 0.5 seconds.

[0021] Preferably, the micro metamorphic structure successively passes through the first temperature and the second temperature, and finally switches from the initial form to the second metamorphic form, realizing a turning motion of nearly 90 degrees.

[0022] Preferably, the first temperature is 45 - 55 °C, and the second temperature is 55 - 65 °C.

[0023] Preferably, the extending directions of the first connecting part and the second connecting part are on the same side of the deformation part before self - deformation.

[0024] Preferably, the materials of the first connecting part and the second connecting part are carbon fiber plates. A carbon fiber plate is formed by infiltrating and hardening carbon fibers arranged in the same direction with resin, and has good properties such as high tensile strength, corrosion resistance, earthquake resistance, and impact resistance, and is suitable for making the fuselage of the micro metamorphic structure. The material of the deformation part is a material that deforms with temperature. Preferably, the material is a shape memory alloy. The shape memory alloy will deform when subjected to temperature changes. The shape memory alloy system includes but is not limited to: Au - Cd, Ag - Cd, Cu - Zn, Cu - Zn - Al, Cu - Zn - Sn, Cu - Zn - Si, Cu - Sn, Cu - Zn - Ga, In - Ti, Au - Cu - Zn, NiAl, Fe - Pt, Ti - Ni, Ti - Ni - Pd, Ti - Nb, U - Nb, and Fe - Mn - Si, etc.

[0025] Preferably, the deformation part is in a long strip shape.

[0026] The second object of the present invention is to provide a manufacturing method of the micro metamorphic structure as described above, including: setting the memory shape of the deformation part of the connection unit; manufacturing the connection unit by using the deformation part and the connection part; connecting multiple connection units to form the moving platform, fixed platform, and moving link of the micro metamorphic structure.

[0027] Preferably, the manufacturing method of the connection unit includes: fixing the deformation part; embedding the deformation part into the corresponding patterned connection part, and patterning can facilitate the connection between the deformation part and the connection part; connecting the deformation part and the connection part; cutting to form the connection unit. The connection between the deformation part and the connection part can be a fixed connection or a detachable connection, and can be any known connection method such as bonding or snap connection.

[0028] Preferably, the method for setting the memory shape of the deformation part includes: manufacturing the deformation part into a preset shape; keeping the deformation part in the preset shape while performing heat treatment on the deformation part; cooling the deformation part, and the memory shape of the deformation part is the preset shape.

[0029] Preferably, the heat treatment temperature is 400 - 900 °C.

[0030] Compared with the prior art, the present invention has the following beneficial effects: 1) The present invention utilizes the autonomous deformation of the deformation part and the overall cooperative effect of the parallel mechanism, taking the deformation part as the rotating shaft, enabling the micro variable cell structure to achieve overall cooperative control only relying on the change of the overall temperature, that is, controlling a specific rotating shaft to generate a specific deformation and controlling the remaining specific rotating shafts not to generate deformation, realizing the variable cell process corresponding to a specific screw, generating a controllable variable cell form, and completing a large deformation of the micro variable cell structure in a short time, achieving a fast and controllable switching between different variable cell forms, and the switching time can be controlled within one second, overcoming the technical prejudice of the prior art (i.e., local heating can only control a specific rotating shaft to generate deformation and cannot control the remaining specific rotating shafts not to generate deformation, and once heated, the material that deforms with temperature will inevitably deform), omitting the separate control equipment or complex scanning procedures required by the prior art, such as laser scanning equipment, laser scanning programs, etc., greatly reducing the control difficulty.

[0031] 2) The present invention utilizes the autonomous deformation of the deformation part and the overall cooperative effect of the parallel mechanism, taking the deformation part as the rotating shaft, enabling the micro variable cell structure to achieve overall cooperative control only relying on the change of the overall temperature, omitting the driving components required by the prior art, such as motors / servos, etc., greatly reducing the size of the micro variable cell structure, and successfully controlling the micro variable cell structure within the millimeter level, expanding the application scenarios of the micro robot with this micro variable cell structure.

[0032] 3) The present invention utilizes the autonomous deformation of the deformation part and the overall cooperative effect of the parallel mechanism, taking the deformation part as the rotating shaft, enabling the micro variable cell structure to achieve overall cooperative control only relying on the change of the overall temperature, omitting the cables required by traditional driving, providing a more convenient driving method applicable to micro mechanical structures, realizing untethered movement, and expanding the moving range. Description of the Drawings

[0033] The accompanying drawings that form a part of this application are used to provide a further understanding of this application, making other features, objectives, and beneficial effects of this application more obvious. The schematic embodiments of the drawings of this application and their descriptions are used to explain this application and do not constitute an improper limitation of this application. In the drawings:

[0034] Figure 1 is a physical diagram of the micro variable cell structure provided by an embodiment of this application;

[0035] Figure 2 is a schematic structural diagram of the connection unit provided by an embodiment of this application;

[0036] Figure 3A and Figure 3B are respectively schematic diagrams of different deformations of the connection unit provided by an embodiment of this application;

[0037] Figure 4A 、 Figure 4B and Figure 4C are physical diagrams of three variable cell forms of the micro variable cell structure provided by an embodiment of this application, Figure 4D 、 Figure 4E and Figure 4F are equivalent structural diagrams of the parallel mechanisms of three variable cell forms of the micro variable cell structure provided by an embodiment of this application;

[0038] Figure 5 is a flowchart of the manufacturing method of the connection unit provided by an embodiment of this application;

[0039] Figure 6 is a schematic diagram of the manufacturing method of the connection unit provided by an embodiment of this application;

[0040] Figure 7 is a curve graph of the self-deformation of the deformation part of the connection unit with temperature provided by an embodiment of this application;

[0041] Figure 8 is an equivalent structural diagram of the parallel mechanism provided by an embodiment of this application;

[0042] Figure 9 is a curve graph of the self-deformation of the deformation part of the connection unit with temperature provided by an embodiment of this application;

[0043] Figure 10 is a curve graph of the self-deformation of the deformation part of the connection unit with temperature provided by an embodiment of this application;

[0044] Figure 11 is a curve graph of the self-deformation of the deformation part of the connection unit with temperature provided by an embodiment of this application;

[0045] Figure 12It is a switching diagram of two metamorphic forms of the micro metamorphic structure provided by the embodiments of the present application;

[0046] Figure 13 It is a switching diagram of two metamorphic forms of the micro metamorphic structure provided by the embodiments of the present application;

[0047] Figure 14 It is a relationship curve diagram of the reconstruction completion time and temperature of the micro metamorphic structure provided by the embodiments of the present application;

[0048] Figure 15 It is a stiffness test diagram of the connection unit provided by the embodiments of the present application;

[0049] Reference numerals: 1 - parallel mechanism; 2 - support structure; 3 - connection unit; 31 - deformation part; 32 - connection part; 41 - shape memory alloy; 42 - glass fiber sheet; 43 - carbon fiber board. Detailed implementation manners

[0050] In order to enable those skilled in the art to better understand the solutions of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0051] It should be noted that the terms "first", "second", etc. in the description and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and do not necessarily need to be used to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so as to describe the embodiments of the present application here. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device including a series of steps or units does not necessarily need to be limited to those clearly listed steps or units, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0052] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The present application will be described in detail below with reference to the drawings and in combination with the embodiments.

[0053] As Figure 1As shown in the figure, this embodiment provides a micro variable cell structure, including a parallel mechanism 1 and four support structures 2 for supporting the parallel mechanism 1. The four support structures 2 are connected to the bottom of the parallel mechanism 1 to support the parallel mechanism 1. Both the parallel mechanism 1 and the support structures 2 are composed of a plurality of interconnected connection units 3. As Figure 1 shown, the parallel mechanism 1 of the micro variable cell structure is a closed loop formed by connecting eight connection units 3, and the eight connection units 3 are respectively represented by A, E, G, C, F, H, D, and B. The four support structures 2 of the micro variable cell structure include four connection units 3, which are respectively represented by P1, P2, P3, and P4.

[0054] As Figure 2 shown, the connection unit 3 includes a deformation part 31 and two connection parts 32. The first end of the deformation part 31 is connected to the first connection part in the connection part 32, and the second end of the deformation part 31 is connected to the second connection part in the connection part 32. The deformation part 31 undergoes autonomous deformation with the change of temperature, so that the spatial relative positions of the two connection parts 32 connected to the first end and the second end of the deformation part 31 change with the autonomous deformation of the deformation part 31. The extension directions of the first connection part and the second connection part are on the same side of the deformation part 31 before autonomous deformation. As Figure 3A or Figure 3B shown. By regulating the overall temperature of the micro variable cell structure, the constraint conditions of the parallel mechanism 1 change, that is, the moving platform and the fixed platform are transformed into moving branches, and the moving branches are transformed into the moving platform and the fixed platform, so as to realize the switching of various variable cell forms of the micro variable cell structure.

[0055] The micro variable cell structure provided in this embodiment includes three variable cell forms, namely the initial form, the first variable cell form, and the second variable cell form, as shown respectively in Figures 4A - 4C the figure, and the corresponding equivalent structure diagrams of its parallel mechanism are shown respectively in Figures 4D - 4F the figure. As Figure 4A shown, the deformation angles of the deformation parts at A and E are 180±40 degrees, the deformation angles of the deformation parts at B, D, F, and H are 90±40 degrees, the deformation angles of the deformation parts at C and G are 180±40 degrees, and the deformation angles of the deformation parts at P1 - P4 are 180±40 degrees. This embodiment sets this variable cell form as the initial form, which can be regarded as a "puppy" mimicry for imitating the posture of a "puppy". The body orientation of the "puppy" is the direction of the connection line between A and E. As Figure 4B shown, the deformation angles of the deformation parts at A and E are 0±40 degrees, the deformation angles of the deformation parts at B, D, F, and H are 90±40 degrees, the deformation angles of the deformation parts at C and G are 180±40 degrees, and the deformation angles of the deformation parts at P1 - P4 are 90±40 degrees. This embodiment sets this variable cell form as the first variable cell form, which can be regarded as a "spider" mimicry for imitating the posture of a "spider". As Figure 4CAs shown, the deformation part angles at A and E are 0 ± 40 degrees, the deformation part angles at B, D, F, and H are 180 ± 40 degrees, the deformation part angles at C and G are 0 ± 40 degrees, and the deformation part angles at P1 - P4 are 90 ± 40 degrees. In this embodiment, this metamorphic cell form is called the second metamorphic cell form, which can be regarded as mimicking the "stick insect" for imitating the posture of the "stick insect". Among them, the body orientation of the "stick insect" is the direction of the line connecting C and G. Therefore, switching from the initial form to the second metamorphic cell form realizes a turning movement of nearly 90 degrees.

[0056] The manufacturing method of the micro - metamorphic cell structure includes: setting the memory shape of the deformation part 31 of the connection unit 3; manufacturing the connection unit 3 using the deformation part 31 and the connection part 32; connecting multiple connection units 3 to each other to form the moving platform, fixed platform, and motion branch chain of the micro - metamorphic cell structure. In this embodiment, the material of the deformation part 31 is nitinol in the shape - memory alloy 41, where the nickel content is 54% - 56%, and the material of the connection part 32 is a carbon fiber board 43. The manufacturing method of the connection unit 3 of the micro - metamorphic cell structure is as Figure 5 shown, including: clamping the shape - memory alloy 41 with a fixture; embedding the fixture and the shape - memory alloy 41 between two layers of patterned carbon fiber boards 43; bonding the shape - memory alloy 41 and the carbon fiber board 43; removing the fixture; and cutting to form the connection unit 3. Specifically, the manufacturing process of the connection unit 3 is as Figure 6 shown: First, make the shape - memory alloy 41 into a strip - like structure, and then fix it between two carbon fiber boards 43 with a glass fiber sheet 42 (fixture). Since the thickness of the glass fiber sheet 42 is greater than the sum of the thicknesses of one carbon fiber board 43 (connection part 32) and one shape - memory alloy 41, and less than the sum of the thicknesses of two carbon fiber boards 43 and one shape - memory alloy 41, it is equivalent to the shape - memory alloy 41 being buckled into the middle of the two carbon fiber boards 43. After bonding the carbon fiber board 43 and the shape - memory alloy 41, as Figure 6 shown in (b) and (c), take out part of the glass fiber sheet 42, and finally cut out the connection unit 3, as Figure 6 shown in (d). The method of setting the memory shape of the shape - memory alloy 41 includes: bending the shape - memory alloy 41 to a preset shape; keeping the shape - memory alloy 41 in the preset shape while heating the shape - memory alloy 41 to the heat - treatment temperature of 400 - 900 °C; after cooling (less than 45 °C) the shape - memory alloy 41, bending the shape - memory alloy 41 back to the initial shape, and the memory shape of the shape - memory alloy 41 is the preset shape.

[0057] When the temperature of the deformation part 31 reaches the temperature required for autonomous deformation, the deformation part 31 autonomously deforms from the initial shape to the corresponding memory shape. The temperatures required for different deformation parts 31 to undergo autonomous deformation are different, which is related to the material of the deformation part 31 and the heat treatment temperature (Xu H, Yong L. Effect of annealing on the transformation behavior and superelasticity of NiTi shape memory alloy [J]. Scripta Materialia, 2001, 45(2): 153-160.). Therefore, by heating the whole to different temperature conditions, specific autonomous deformations can be controlled to occur in specific deformation parts 31, and specific other deformation parts 31 can be controlled not to undergo autonomous deformation.

[0058] In this embodiment, the shape memory alloys of the deformation parts 31 in different connection units 3 were processed in two batches. That is, the shape memory alloys of the deformation parts 31 of C, G, F, H, D, and B were in one batch, and the shape memory alloys of the deformation parts 31 of A, E, P1, P2, P3, and P4 were in one batch. The heat treatment temperature of the former was 550 °C, and the heat treatment temperature of the latter was 500 °C. The heat treatment time was 2 hours for both, and then they were both cooled to room temperature. Subsequently, the cooled shape memory alloy 41 needs to be repeatedly subjected to cold-hot cycle treatment more than 10 times in an ice-water mixture at 0 °C and boiling water close to 100 °C to make it have a stable memory shape.

[0059] The initial shapes, memory shapes, and temperature conditions for the autonomous deformation of the deformation parts 31 of each connection unit 3 composed of the shape memory alloy 41 after the above treatment are as follows. Among them, the deformation part angle refers to the angle between the extension directions of the two connection parts 32 connected to the deformation part 31, that is, Figure 8 shown by θ in Figure 8 (the deformation part 31 is equivalent to Figure 8 the rotating shaft in Figure 7 , and the connection part 32 is equivalent to Figure 1 the connecting rod in Figure 8 ). Due to process limitations, there is a gap between the actual deformation situation and the ideal situation, and there is an error of about 40 degrees in the deformation part angle: The initial shape of the deformation part 31 of A and E is: the deformation part angle is 180 ± 40 degrees, the memory shape is: the deformation part angle is 0 ± 40 degrees, and the temperature condition for the deformation part 31 to undergo autonomous deformation is to reach 45-55 °C; The actual deformation situation of the deformation parts of A and E is as shown in Figure 7 . In addition, considering the feasibility of physical manufacturing, the deformation part 31 of A and E is different in the physical drawing ( Figure 1 ) and its equivalent structure drawing ( Figure 8 ), and the equivalent structure drawing ( Figure 8) Among them, the angular change of the deformation parts of A and E changes from 0 degrees to 180 degrees, while the angular change of the deformation parts of A and E in the physical diagram changes from 180 ± 40 degrees to 0 ± 40 degrees.

[0060] The initial shapes of the deformation parts 31 of B, D, F, and H are: the deformation part angle is 90 ± 40 degrees, the memory shape is: the deformation part angle is 180 ± 40 degrees, and the temperature condition for the deformation part 31 to undergo autonomous deformation is to reach 55 - 65 °C; the actual deformation conditions of the deformation parts 31 of B, D, F, and H are as Figure 9 shown.

[0061] The initial shapes of the deformation parts 31 of C and G are: the deformation part angle is 180 ± 40 degrees, the memory shape is: the deformation part angle is 0 ± 40 degrees, and the temperature condition for the deformation part 31 to undergo autonomous deformation is to reach 55 - 65 °C; the actual deformation conditions of the deformation parts 31 of C and G are as Figure 10 shown.

[0062] The initial shapes of the deformation parts 31 of P1, P2, P3, and P4 are: the deformation part angle is 180 ± 40 degrees, the memory shape is: the deformation part angle is 90 ± 40 degrees, and the temperature condition for the deformation part 31 to undergo autonomous deformation is to reach 45 - 55 °C; the actual deformation conditions of the deformation parts 31 of P1, P2, P3, and P4 are as Figure 11 shown.

[0063] In this embodiment, by placing the micro metamorphic cell structure in hot water, the temperature of the hot water is controlled to achieve overall heating of the micro metamorphic cell structure. Additionally, overall heating of the micro metamorphic cell structure can also be achieved by pouring hot water, blowing hot air, etc. The mechanical principle of the switching process of the micro metamorphic cell structure to different metamorphic forms will be described below in combination with screw calculation. The equivalent structure diagram of the parallel mechanism 1 of the micro metamorphic cell structure in this embodiment is as Figure 8 shown, which is composed of eight rotating shafts connected by eight connecting rods. The deformation part 31 in the parallel mechanism 1 is equivalent to Figure 8 the rotating shaft in Figure 8 and the connecting part 32 is equivalent to

[0064] the connecting rod in

[0065] such as Figure 12As shown, when the temperature of the micro-variable cell structure rises to 45 - 55 °C, the deformation parts 31 of A and E autonomously deform from the initial shape (the angle of the deformation part is 180 ± 40 degrees) to the corresponding memory shape (the angle of the deformation part is 0 ± 40 degrees); the deformation parts 31 of P1, P2, P3, and P4 autonomously deform from the initial shape (the angle of the deformation part is 180 ± 40 degrees) to the corresponding memory shape (90 ± 40 degrees); at the same time, the deformation parts 31 of C, G, F, H, D, and B do not undergo autonomous deformation, and the micro-variable cell structure switches from the initial form to the first variable cell form, and the switching time is 2 seconds.

[0066] Switching from the initial initial form to the first variable cell form, the corresponding screw calculation process is as follows: As Figure 8 shown, during this variable cell process, the moving platform is BCD, the fixed platform is FGH, the first moving chain is HAB, and the second moving chain is FED. The first rotating shaft at A and the second rotating shaft at E are parallel to the x-axis. The third to fifth rotating shafts at F, G, and H are parallel to each other and are arranged on the fixed platform FGH, and the sixth to eighth rotating shafts at D, C, and B are parallel to each other and are arranged on the moving platform BCD. The third to eighth rotating shafts are all perpendicular to the first rotating shaft. In this embodiment, the motion screw system S f formed by the first moving chain and the second moving chain is:

[0067]

[0068] Among them, S f1 is the motion screw of the first rotating shaft of the first moving chain, and S f2 is the motion screw of the second rotating shaft of the second moving chain.

[0069] The constraint screw system S r of the parallel mechanism 1 is:

[0070]

[0071] Among them, S1 r , S2 r , S3 r , S4 r , S5 r are the first to fifth force constraint screws respectively.

[0072] The motion screw system S m of the moving platform is: S m = [1 0 0 0 0 0] T .

[0073] It can be obtained that when the movements of the first rotating shaft at A and the second rotating shaft at E on the moving branch chain are synchronized, the moving platform BCD rotates around the x-axis relative to the fixed platform FGH. Correspondingly, the micro metamorphic structure realizes the switching between the initial form and the first metamorphic form, as Figure 12 shown.

[0074] Metamorphic process two: Switching from the first metamorphic form to the second metamorphic form.

[0075] As Figure 13 shown, on the basis of metamorphic process one, when the temperature continues to rise to 55 - 65 °C, the deformation parts 31 of C and G autonomously deform from the initial shape (the angle of the deformation part is 180 ± 40 degrees) to the corresponding memory shape (the angle of the deformation part is 0 ± 40 degrees); the deformation parts 31 of B, D, F, and H autonomously deform from the initial shape (the angle of the deformation part is 90 ± 40 degrees) to the corresponding memory shape (the angle of the deformation part is 180 ± 40 degrees); at the same time, the deformation parts 31 of A, E, P1, P2, P3, and P4 stop autonomous deformation (remain in the memory shape); the micro metamorphic structure switches from the first metamorphic form to the second metamorphic form, and the switching time is 0.4 seconds.

[0076] When the micro metamorphic structure switches from the first metamorphic form to the second metamorphic form, the corresponding screw calculation process is as follows: As Figure 8 shown, in this metamorphic process, the moving platform is DEF, the fixed platform is HAB, the first moving branch chain connecting the moving platform and the fixed platform is DCB, and the second moving branch chain is FGH (it can be seen that compared with metamorphic process one, the platform and the moving branch chain are transformed).

[0077] Among them, the first rotating shaft at A is on the fixed platform and is parallel to the x-axis; the second rotating shaft at E is on the moving platform, is parallel to the first rotating shaft and is connected through the first moving branch chain and the second moving branch chain; the third to fifth rotating shafts are parallel to each other and perpendicular to the first rotating shaft, and are all arranged on the first moving branch chain; the third rotating shaft is connected to the first rotating shaft through a connecting rod, and the length of the connecting rod is r; the fourth rotating shaft is respectively connected to the third rotating shaft and the fifth rotating shaft through connecting rods, and the lengths of the connecting rods are both l; the fifth rotating shaft is connected to the second rotating shaft through a connecting rod, and the length of the connecting rod is r; the sixth to eighth rotating shafts are parallel to each other and perpendicular to the first rotating shaft, and are all arranged on the second moving branch chain; the sixth rotating shaft is connected to the first rotating shaft through a connecting rod, and the length of the connecting rod is r; the seventh rotating shaft is respectively connected to the sixth rotating shaft and the eighth rotating shaft through connecting rods, and the lengths of the connecting rods are both l; the eighth rotating shaft is connected to the second rotating shaft through a connecting rod, and the length of the connecting rod is r.

[0078] The motion screw system S composed of the first moving branch chain and the second moving branch chain f is:

[0079]

[0080] Among them, S f11 is the constraint screw at the third rotating shaft, and S f12 is the constraint screw at the fourth rotating shaft, and S f13 is the constraint screw at the fifth rotating shaft, and S f21 is the constraint screw at the sixth rotating shaft, and S f22 is the constraint screw at the seventh rotating shaft, and S f23 is the constraint screw at the eighth rotating shaft, and θ is the included angle between the connecting rods connecting the first rotating shaft to the third rotating shaft and the sixth rotating shaft respectively.

[0081] The constraint screw system S r of the parallel mechanism 1 is:

[0082]

[0083] Among them, S1 r , S2 r , S3 r , S4 r , S5 r are the first to fifth force constraint screws respectively;

[0084] The motion screw system S m of the moving platform is: S m = [0 0 0 1 0 0] T .

[0085] It can be obtained therefrom that when the third to fifth rotating shafts at F, G, and H on the moving branch chain are synchronized with the motions of the sixth to eighth rotating shafts at D, C, and B respectively, the moving platform DEF performs a linear motion along the x-axis relative to the fixed platform HAB. Correspondingly, the micro variable cell structure realizes the switching between the first variable cell form and the second variable cell form, as Figure 13 shown.

[0086] Variable cell process three: Switching from the initial form to the first variable cell form and then to the second variable cell form.

[0087] As Figure 14 shown, it is the relationship curve between the reconstruction completion time of the micro variable cell structure (the total time required to switch from the initial form to the first variable cell form and then to the second variable cell form) and the temperature. It can be seen that the higher the temperature, the faster the reconstruction completion time. When the temperature of the micro variable cell structure is between 55 - 65 °C, switching from the initial form to the first variable cell form and then to the second variable cell form, the reconstruction completion time is only 0.5 seconds. The body orientation of the initial form (which can be regarded as the direction of the connecting line of the rotating shafts at A and E) and the body orientation of the second variable cell form (which can be regarded as the direction of the connecting line of the rotating shafts at C and G) differ by 90 degrees. Therefore, in this embodiment, the micro variable cell structure can achieve a turning motion of nearly 90 degrees in only 0.5 seconds.

[0088] In the initial form, the length, width and height of the micro metamorphic structure can reach 42 mm, 20 mm and 40 mm respectively; in the first metamorphic form, the length, width and height of the micro metamorphic structure can reach 45 mm, 45 mm and 20 mm respectively; in the second metamorphic form, the length, width and height of the micro metamorphic structure can reach 50 mm, 30 mm and 20 mm respectively, successfully controlling the micro metamorphic structure at the millimeter level. During the metamorphosis of the micro metamorphic structure, the scale change of the overall structure is as high as 26%, and the single scale change is as high as 125%.

[0089] Figure 15 It is a stiffness test diagram of the connecting unit 3. Among them, when the temperature of the micro metamorphic structure reaches 45 - 80 °C, the stiffness test curve of the connecting unit 3 is Figure 15 shown by the solid line (Test2) in [the figure]. After cooling, that is, when the temperature of the micro metamorphic structure is less than 45 °C, the stiffness test curve of the connecting unit 3 is Figure 15 shown by the dashed line (Test1) in [the figure].

[0090] The above are only the preferred embodiments of the present application and are not used to limit the present application. For those skilled in the art, various changes and modifications can be made to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included within the protection scope of the present application.

Claims

1. A micro metamorphic structure, characterized in that It includes a parallel mechanism (1), and the parallel mechanism (1) includes a platform and kinematic chains composed of a plurality of interconnected connection units (3). The platform includes a moving platform and a fixed platform. The connection unit (3) includes a deformation part (31) and two connection parts (32). The first end of the deformation part (31) is connected to the first connection part among the connection parts (32), and the second end of the deformation part (31) is connected to the second connection part among the connection parts (32). By changing the overall temperature of the micro metamorphic structure, partial or all of the deformation parts (31) generate autonomous deformation to the corresponding memory shapes. The two connection parts (32) connected to the first end and the second end of the deformation part (31) change their relative spatial positions, and a conversion occurs between the platform and the kinematic chains, thereby realizing the switching of multiple metamorphic forms. The micro metamorphic structure has an initial form. When the overall temperature of the micro metamorphic structure reaches the first temperature, the deformation parts (31) on the kinematic chains generate autonomous deformation, causing the moving platform to rotate around the fixed platform. The micro metamorphic structure realizes the switching between the initial form and the first metamorphic form. Based on the first metamorphic form, when the overall temperature of the micro metamorphic structure reaches the second temperature, and the second temperature is higher than the first temperature, a conversion occurs between the platform and the kinematic chains. The deformation parts (31) on the kinematic chains obtained after the conversion generate autonomous deformation, causing the moving platform obtained after the conversion to perform linear motion relative to the fixed platform obtained after the conversion. The micro metamorphic structure realizes the switching between the first metamorphic form and the second metamorphic form.

2. The micro-variable cell structure according to claim 1, characterized in that When the micro metamorphic structure realizes the switching between the initial form and the first metamorphic form, the angular change amplitude of the deformation parts (31) on the kinematic chains is more than 100 degrees.

3. The micro variable cell structure according to claim 1, characterized in that When the micro metamorphic structure realizes the switching between the first metamorphic form and the second metamorphic form, the angular change amplitude of some of the deformation parts (31) on the kinematic chains obtained after the conversion is more than 100 degrees.

4. The micro-variable cell structure according to claim 1, characterized in that The first temperature is 45 - 55 °C, and the second temperature is 55 - 65 °C.

5. The micro variable cell structure according to claim 1, characterized in that, The micro metamorphic structure further includes one or more support structures (2) for supporting the parallel mechanism (1).

6. A manufacturing method of a micro variable cell structure according to any one of claims 1-5, characterized in that, It includes: Setting the memory shapes of the deformation parts (31) of the connection unit (3); Using the deformation parts (31) and the connection parts (32) to fabricate the connection unit (3); Mutually connecting a plurality of the connection units (3) to form the moving platform, the fixed platform, and the kinematic chains of the micro metamorphic structure.

7. The manufacturing method of the micro metamorphic cell structure according to claim 6, characterized in that, The manufacturing method of the connection unit includes: Fixing the deformation part (31); Embedding the deformation part (31) into the corresponding patterned connection part (32); Connecting the deformation part (31) and the connection part (32); Cutting to form the connection unit (3).

8. The manufacturing method of the micro metamorphic structure according to claim 6, characterized in that, The method for setting the memory shapes of the deformation parts (31) includes: Fabricating the deformation part (31) into a preset shape; Keep the deformation part (31) in the preset shape and perform heat treatment on the deformation part (31) at the same time; Cool the deformation part (31), and the memory shape of the deformation part (31) is the preset shape.

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